Steam heating system for automobile bodies



Oct. 13, 1936. R. w. ANGSTMAN 2,057,128

STEAM HEATING SYSTEM FOR AUTOMOBILE BODIES Original Filed June 6, 1934l/kw 2/ 3INVENT0R Roger szman.

Patented Oct. 13, 1936 UNITED STATES PAiTE-NT- OFFICE STEAM HEATINGSYSTEM FOR AUTO- MOBILE BODIES Roger W. Angstman, Detroit, Mich,assignor to McAleer Manufacturing Company, a corporation of Michigan 9Claims. (01. 2si* ,12.a)

This invention relates to motor vehicle heating systems and moreparticularly to systems which utilize the waste heat from the exhaustgases of the internal combustion engine which drives the vehicle togenerate steam or vapor from the water or other liquid in the coolingsystem of the engine, the steam or vapor then being passed through aradiator or radiators to heat the interior of the body of the vehicle,and is a division of my application for Letters Patent of the UnitedStates filed June 6, 1934 for improvements in Steam heating systems forautomobiles, Serial No. 729,212, now Patent No. 1,990,159, issuedFebruary 5, 1935.

The principal object of the present invention is to provide means forautomatically reducing the temperature of the steam being fed from thesteam generator to the heater radiator under those conditions ofoperation during which the temperature of such steam may approach and/or exceed a value which may prove deleterious to the heater radiator.

Other objects of the invention includes the provision of an automobilesteam heating system including a steam generator and a heater radiatorin which means are provided for reducing the temperature of the steambeing fed to the heater radiator during certain conditions of engineoperation; the provision of means in connection with a device of thetype described for discharging super-heated steam from the steamgenerator to the vehicle cooling system; the provision of an automobilebody steam heating system including a steam generator heated by theexhaust gases of the engine, and a heater radiator to which steam fromthe generator is normally fed, together with means for discharging steamonly under certain conditions of operation from the generator andreturning it to the engine cooling system without passing it through theheater radiator; the provision of an automobile steam heating systemincluding a steam generator and heater radiator connected in circuitwith different portions of the liquid cooling system for the engine ofthe automobile, and a by-pass between the inlet side of the steamgenerator and the engine cooling system for returning a portion of thesteam formed in the generator, independently of the heater radiator, tothe engine cooling system during certain conditions of engine operation;the provision of means in a construction as above described for reducingthe effect which super-heated steam formed in the steam generator wouldotherwise have on the heater radiator, comprising a duct connecting theinlet side of the steam generator with the engine cooling system, and aspring pressed check valve in the duct so constructed and arranged as tobypass fluid from the generator to the engine cooling systemindependently of the heater radiator 5 under those conditions of engineoperation conducive to the formation of super-heated steam in the steamgenerator.

Further objects of the invention include the provision of a method ofoperating an automobile 10 body steam heating system so as to preventthe introduction of excessive volumes of'steam at excessively hightemperatures to the heater radiator; and the method of operating anautomobile body steam heating system including a steam generator :and aheater radiator connected in circuit with different portions of thecooling system for the automobile engine so as to prevent theintroduction of excessive amounts of steam of excessively hightemperatures to the heater radiator by returning a portion of suchexcessively high temperature steam from the steam generator to theengine cooling system so as to prevent such portion of such steam frombeing fed tothe heater radiator.

The above being among the objects of the present invention the sameconsists in certain novel features of construction, combinations ofparts and method of operation to be hereinafter described with referenceto the accompanying drawing, and then claimed, having the above andother objects in view. I

In the accompanying drawing which illustrates a suitable embodiment ofthe present invention and in which like numerals refer to like partsthroughout the several different views,

Fig. 1 is a more or less diagrammatic side elevation, partly in section,of a portion of an automotive vehicle illustrating the application of asteam heating system to such vehicle.

and 3 as viewed, for instance on the line 5-5 of Fig. 2.

The present invention deals with that type of ,=-automobi1e body'steamheating-systems in which a steam generator, which may be convenientlyformed of a length of tubing, is so positioned as to be heated by theexhaust gases of the engine ,whichdrives the automobile, and is adaptedto deliver steam generated thereby to a radiator positioned within theautomobile body for the purpose of heating the air in such body. Theinlet end of the steam generator is connected to the tem on oppositesidesof the pump for such cooling system so that a pressure diiferentialwill be created at opposite ends of the body heating system tending'tocause a circulation of fluid from the cooling system therethrough.

The parent patent application from which the present patentapplicationwas divided, as above identified, deals particularly with theintroduction .ofmeans between the discharge side of the body radiatorand the engine cooling system for normally restricting the flow of fluidfrom the body radiator so as to cause a positive pressure to be built uptherein, thereby enhancing the heating effector the body radiator as isdesirable under certain conditions of operation as, for instance,

when the engine is' idling or the automobile is travelling at relativelylow speed at which time the flow of exhaust gases are at a minimum, and

providing means for rendering the restriction inoperative or at least tolimit the restricting ef-.

fects thereof so as to prevent an excessive pressurefromfbeing built upinfthe body radiator at such engine speeds that the flow of exhaustgases is 'in excessof that required'to provide the necessary flow of:s'team'for adequate body heating purposes. Such restricting feature,while it may be employed in connection with thepresent' invention, isentirely independent thereof and the present' invention is not to belimited thereby.

It has been found in connection with automobile bodylstea'm heatingsystems of the type described that under certain conditions of engineoperation, particularly at high speeds and full 'load, that the amountof heat being transferred from the exhaust gases of the' engine to thewater or, other liquid in the steam generator of the automobile'body'steam heating system is more than sufficient to turn such liquidinto steam, and accordingly super-heats the steam thus formed.

' m extreme conditions at least the amount of super-heat thus impartedto the steam and which steam'is consequently fed to the body radiator isof sufficiently high temperature to melt the solder holding and sealingthe various" parts of the radiator together, thus permitting the highlysuper-heated steam to escape into the interior of r V r theautomobilebody where it may constitute a danger and menace to the'occupantsthereof. The present inventionprovides a means whereby thedestructiveefiects of such super-heated steam on the heater radiator maybe eliminated but without rendering the heater any less efiective duringnormal operation at lower speeds.

The effect of such super-heated steam generated by the steam generatoron the heater radiator is to all practical purposes eliminated orreduced by feeding a suificient amount of such superheated steamdirectly back to the engine cooling system without its having'passedthrough the heater radiator. Inother words, only a. portion of thesuper-heated steam generated ispermitted to passthrough the heaterradiator. V In this manner theamount of super-heated steam fed to theheater radiator is of such small volume that its excessive heat contentis dissipated by the radiator before it has an opportunity to raise thetemperature of the radiator to such an extent as to cause damagethereto. This is accomplished by providing a duct connected at one endto the steam generator as close as possible to the hottest point thereinand preferably adjacent to the inlet end thereof and connected at itsopposite end with the engine cooling system, and providing a Springpressed check valve in the duct so constructed and arranged to permitfluid to be by-passed through the duct from the steam generator to theengine cooling system only under those conditions of operation underwhich the formation of super,- heated steam in the steam generator isliable to occur. Obviously the point of connection of this duct withtheengine cooling system is more or less immaterial as long as it permitsthe discharge of super-heated fluid from the steam generatorindependently of the heater radiator, but ordinarily it will be foundpreferable to con- 'nect it with the engine cooling system on thesucsubjectedto the pressures simultaneously exist ing at the inlet endof the steam generator. It

must, however, be connected on the down stream .side of the check valveand the check valve 40 should be placed as close as convenientlypossible .to the inlet endofthegenerator and as close as possibleto thepoint where such end is in contact with the exhaust gases. 7 g 7Referring to the drawing, the numeral l I indicates an internalcombustion engine of the type I usually employed in'motor'vehicles andhaving a radiator 12 in front of the same as a part of the cooling.system of the engine, the radiator having its upper and lower portionsconnected with the corresponding portions of the water jacket I3of theengine by means of conduits l4 and I5 respectively A pump I6 isinterposed, in circuit, between the conduit I5 and 'the lower portion ofthe water jacket l3 to cause a forced circulation in thecooling systemof the, engine during operation of the latter. The engine is providedwith an. exhaust manifold l1 and an exhaust pipe 20 for conducting theexhaust gases from the engine to a suitablepoint of discharge.

A steam generator 2| is associated'with the exhaust pipe 2|] and, asillustrated in Fig. 1, for the purpose of illustration, is shown asconsisting of to the upper portion of the. water jacket l3 through athrottling or metering valve means 25,

connected into the water jacket l3 at this point. The valve means 25 isprovided-forthe purpose of controlling the rate of flow of feed waterfrom v the cooling system of the enginev to the'steam generator.

I Reference may now behad to Fig. 2 which illustrates the constructionof the valve 25 more in detail. The supply valve 25 comprises a bodycasting 26 provided with a strainer chamber 21' communicating at one endwith the conduit portion leading from the top of the water jacket I3 orother points in the cooling system on the high pressure side of thecirculatingpump, and communicating through an orifice 28 leading intothe side of the chamber 27 and communicating with the conduit 23 leadingto the steam generator 2|. A needle valve stem 30 is threaded into thesupply valve body 26 and arranged to regulate the flow through therestricted orifice 28. A needle valve adjustment knob 3| is secured tothe end of the needle valve stem 30 for rotating the latter so as toregulate the effective opening of the orifice 28 and thus restrict;throttle and/or meter the amount of water flowing through the valve 25so that the desired amount of water will be fed to the steam generator.The needle valve adjusting spring 32 is secured to the sup-ply valvebody 26 by means of a lock nut 33 and cooperates with the periphery ofthe adjustment knob so as to retain the needle valve in the desiredadjusted position. A packing nut 34 and packing 35 are employed toeffect a seal about the valve stem 30. One end of the strainer chamber21 may be closed by a plug 36 threaded to the supply valve body 26 tohold the strainer 31 in position, and removable therefrom for thepurpose of cleaning or replacing the strainer 31 which is employed toseparate out scale, dirt or other foreign matter from cooling liquidpassed through the valve so that such foreign matter will not beconveyed by the liquid into the heating system.

Referring now to Figs. 1 and 4 it will be noted that a check valve 46 isinterposed between the feed water conduit 23 and the steam generator 2|and that the location of the valve 46 is in close proximity to the pointwhere the inlet end of the generator 2| extends through the exhaust pipe20. The valve 46 comprises a body 4| provided with a chamber 42 in whichis disposed a gravity operated check valve flapper 43 pivoted to thevalve body 4| as indicated at 44, and adapted to close a valve port 45against the flow from right to left as viewed in Fig. 4 but to permitflow from left to right through the valve port 45. The valve body 4| isprovided with a removable plug 46 which upon removal will permitcleaning, inspection, or replacement of the check valve flapper 43. Forthe purpose of simplicity in construction and economy in manufacture theplug is additionally formed to provide a part of the present invention,but this will be described later and for the present stage ofdescription may be considered simply as a plug.

Referring again to Fig. 1, it'will be noted that the discharge side ofthe steam generator 2| is extended as at 5| to form a conduit connectingthe steam generator with the upper end of a heater radiator 52 adaptedto be arranged within the body of the automobile. The radiator 52comprises upper and lower headers 53 and 54 respectively and tubes 55 orother suitable heat transfer means interconnecting the headers. A returnconduit 56 leads from the bottom header 54 and communicates with theconduit I5 at a point adjacent the inlet of the pump |6. A fan 51operable by a suitable electric motor 58 is mounted in back of thetubes55 or equivalent heat transfer means of the radiator 52 in order tocause a forced circulation of air therethrough. The radiator 52 andmotor and fan assembly may be connected to the dash 60 of the automobilein any suitable manner for supporting the same, a convenient methodbeing to sup-port it by means of the pipes or conduits leading into andout of the upper and lower header thereof.

Reference may now be had to Figs. 1 and 3 which illustrate thearrangement and construction of an exhaust throttling and safety valve6| interposed in the return conduit 56 leading back to the enginecooling system. This valve comprises a body portion 62 provided with alongitudinal passage 63 communicating at the left hand end, as viewed inFig. 3, with the portion of the return conduit 56 and communicating atthe right end with the portion of the return conduit leading to theradiator 52. The passage 63 is provided with an orifice 64 whichcooperates with a needle valve stem 65 threaded to the valve body 62, asindicated at 66, for regulating the effective area of the orifice 64.The valve stem 65 is of the same construction as the valve stem 30illustrated in Fig. 2 and is provided with a similar adjusting knob 16adapted to be locked in fixed position by means of the needle valveadjusting spring H. A by-pass 12 is provided in the valve body 62 andcommunicates with the passage 63 on both sides of the restricted orifice64. A ball valve 13 is adapted to cooperate with a valve port 74provided in the by-pass 12 and is yieldably urged into position closingsuch port by means of a spring 15. A spring retainer nut 16 is threadedto the valve body 62 to retain the spring I5 in compressed condition tourge the ball valve 13 toward its closed position.

The valve 6| is adjusted to impede the flow of water or steam throughthe return conduit 56 so as to cause a positive pressure to be built upwithin the radiator 52 and thereby increase the heating efiect of suchradiator, especially for low operating speed of the engine II. Ifexcessive pressures develop within the radiator 52, these pressures willdepress the ball valve 13 against the force of the spring 15 and by-passsteam or water, or both, through the by-pass passage 72 into the returnconduit 56 to prevent damage to the radiator. The compressive stress ofspring 15 determines the pressure at which the valve 13 will bedepressed and consequently the maximum pressure that may be built up inthe radiator 52.

In the operation of the apparatus thus far described, when the engine His operating, water from the water jacket l3 and which is under thedischarge pressure of the pump IE will be forced through the valve 25 ata rate determined by the setting thereof, through the check valve 40 tothe steam generator 2| where the exhaust gases passing through theexhaust pipe 20 will cause such water to be turned to steam which willflow through the duct 5| to the radiator 52 and after passing throughthe radiator 52 will be returned to the engine cooling system on thesuction side of the pump l6 through the duct 56, the valve 6| normallyretarding the flow from the radiator 52 so as to maintain a positivepressure on the steam within the radiator and which pressure may, forinstance, be from five to seven pounds per square inch gauge. The steamin passing through the radiator 52 will give up heat to the surroundingair and this transfer of heat will be accelerated or increased byoperation of the fan 51 and motor 58. Should the pressure of the steamin the radiator 52 exceed a desirable maximum value the ball valve 13will be moved away from its seat 14 to permit steam to beby-pass'ed'around the stem 65 until the pres sure of the steam in the radiator52'has been reduced to the desired value. Now it will 'be readilyunderstood that the capacity of the steam generator 2i fora givendiameter of tubing, and it may be noted that five-sixteenths inch tubingmay be advantageously employed for the steam generator in the majorityof installations, will be approximately proportional tothe length of Vthe steam generator; Considering that the greatest mileage puton theaverage automobile is at a speed of 30 miles per hour or less, when theengine is running at only part speed and under part load conditions, itwill be understood that the generator 2I should be made of such lengthas to permit an ample supply of steam at such speed to maintain thedesired high degree of temperature in the automobile body. I have found,however, that when the generator is so proportioned and the automobileis driven at relatively high speed and particularly at high speeds'andunder full loads,'the amount of heat transferred to the fluidin j thegeneratoris in excess of that required to turn the water within it intosteam, and'consequently the steam formed becomes super heated, in somecases to such a degree that its temperature is sufficient to melt thesolder employed in the construction of the radiator 52, and when thisoccurs the radiator 52 leaks and allows such super-heated steam toescape into the interior of the automobile body, creating a dangerouscondition.

To overcome this defect and still permit ample amounts of heat to beprovided at lower engine speeds and loads, means are provided aspreviously mentioned for discharging part of the steam formed at higherengine speeds and loads from the system in the immediate vicinity of thesteam generator I3 back to the engine cooling system, thus reducingvolume of-super-heated steam fed under such conditions to the radiator'to such an extent that the. heat thereof may be a point adjacent suchinlet, and as also previously explained this portion of the super-heatedsteam which is removed from the generator may, in' the broader aspectsof the invention, be re- 7 turned to the engine cooling system at anysuitable location but preferably to the cooling systemhon the suctionside of the pump I6 so that the suction of the pump, where present, willaid it in being withdrawn from the steam generator. The particularmethod of doing'this as illustrated in the drawing, by way ofillustration, is to provide a tube between the check valve 40 and theconduit 56 connecting the discharge side of the heat-er radiator 52 withthe connection I 5 betweenthe cooling radiator I2 and the pump I6. Toconnect the by-pass tube or conduit 90 to the check valve 40 the plug.46is provided with a central bore I0I into which the corresponding end ofthe tube 90 may be connected as by threading. The bore IIlI'which leadsintothe hollow interior 42 of the valve body 4| on the down stream sideof the flapper valve 43, is en'- larged as at I02 to provide a shoulder'I03. The lower'end of the bore .I0I is closed by an apertured plug I04which provides a seat for the-ball valve ;'I05 which in turn,is'constantly'urgedtoward seated position by means-of a coil spring I06-maintained under compression between the ball I05 and the shoulder I03.Steam from the generator 2| may thus pass from the discharge end of thegenerator past the ball valve I05 and through" the 'duct .90 ,to thereturn line 56 and thence back to the cooling system of the enginewithout having, passed through the heater radiator 53. In this manner,under those conditions of engine operation at which steam formed in thegenerator 2| is liable to be of a super-heated nature, a sufficientvolume 'of such steam may be discharged directly from the steamgenerator to the engine cooling system without having passed through theheater radiator 52, and where the mechanism is properly proportioned andadjusted' the amounts of super-heated steam thus heat occurs and duringwhich the valve 13 cm the'discharge side of the radiator 52 functions tomaintain a positive pressure in the system. Preferably the force of thespring I06 is such as to require a pressure in the system of two orthree pounds per square inch greater than that required to lift thevalve I3 from its seat, in order for itto operate and by-passsuperheated steam directly back to the cooling system for the enginewithout passing through the radiator 52.

With the above described construction it will be obvious thatparticularly where the valve' 6I maintains a positive pressure on thesteam in the generator 2| and heater radiator 52','the interior of thecheck valve 40 will be subjected to a higher pressure than the pressureexisting in a the return line 56 which is connected to the suc- 'tionside of the pump I6. This normal operating pressure differentialincreases with increased speed of operation of the engine II because of'increased speed of operation of the pump I6 and consequently the forceof, the spring I03 may be so arranged that the ball valve I05 will belifted from its seat to pass steam through'the duct 96 only during thosespeeds of engine operation at which the flow of exhaust gases throughthe exhaust pipe 20 is of such extent as to cause the steam generatedthereby to be super-heated to an undesirable degree. It has beendiscovered, however, that during those phases of engine operation atwhich the steam generated in the generator 2| becomes of a highlysuper-heated nature, relatively violent surges of pressure occur withinthe steam generator and these surges of pressure are found to be ofmaximum value between the points where the inlet to the generator 2Iextends into the exhaust pipe 20 and .the check valve 40. Experimentshave shown maximum pressures built up by these surges as high asfifteenpounds per square inch gauge and probably the reason they are greatestential existing between the high pressure and low pressure sides of theheating system to 1 actuate the" ball' valve I05 unde'r such conditions.A0-

cordingly when these surges occur the ball valve I05 is lifted and aportion of the super-heated steam in the generator 2| is discharged pastthe ball valve I05 through the duct to the return line 56 where it isdrawn by the pump I6 into the cooling system of the engine and issuitably condensed by the lower temperature thereof. The amount ofsuper-heated steam thus fed past the ball valve I05 will depend to someeX- tent upon the force of the spring I03 and accordingly by varying theforce of such spring the amounts of super-heated steam thus fed back tothe engine cooling system may be governed to a greater or lesser extent.In this manner the amount of steam fed from the generator 2| to theheater radiator 52 during such phases of engine operation may be reducedin volume to such an extent that the high heat content thereof may bedissipated in the radiator at such a rate as to prevent the radiator orparts thereof from becoming equally highly heated. At the same time thissmaller amount of heat being fed to the heater radiator 52, because ofits relatively high heat content, will still be found to be ample forthe purpose of heating the interior of the automobile body to thedesired degree. The super-heated steam fed back to the duct 90 andreturn line 56 to the engine cooling system will, of course, have atendency to increase the temperature of the cooling fluid in suchcooling system, but it will be found that this effect is so small as tobe negligible and offers no material problem in this regard.

While but one embodiment of the present invention has been shown in theaccompanying drawing various modifications thereof will be apparent tothose skilled in the art once the teachings herein are disclosed to themand, accordingly, it will be understood that formal changes may be madein the specific embodiment of the invention described without departingfrom the spirit and substance of the broad invention, the scope of whichis commensurate with the appended claims.

What I claim is:

1. In combination with a water cooling system of an internal combustionengine, a heater radiator, a feed pipe connecting said cooling systemand said heater radiator, a steam generator in said feed pipe, a checkvalve in said feed pipe between said cooling system and said generatorfor preventing return flow of fluid from the generator to the coolingsystem through said feed pipe, a return pipe connecting said heaterradiator and said cooling system, a conduit communicating at one endwith the portion of said feed pipe extending between said check valveand said steam generator and at a point therein closely adjacent saidgenerator and at the other end with said water cooling systemindependently of said heater radiator, and pressure responsive means insaid conduit operable in response to a predetermined pressuredifferential between the ends of said conduit to pass fluid from saidsteam generator to said cooling system through said conduit withoutpassing it through said heater radiator.

2. In combination with a water cooling system of an internal combustionengine, a heater radiator, a feed pipe connecting said cooling systemand said heater radiator, a steam generator in said feed pipe, a checkvalve in said feed pipe between said cooling system and said generator,2, return pipe connecting said heater radiator and said cooling system,a conduit communicating at one end with that portion of said feed pipebetween said check valve and said steam generator and at a point thereinclosely adjacent said generator and at the other end with said returnpipe, said conduit being subjected to a varying pressure differentialbetween the ends thereof, and pressure responsive means associated withsaid conduit operable in response to a predetermined pressuredifferential to pass fluid from said generator to said return pipethrough said conduit without said fluid passing through said heaterradiator.

3. In an automobile body steam heating system including a steamgenerator and a body radiator connected in circuit with differentportions of the automobile engine cooling. system and having a meteringdevice and a check valve in the connection for conducting fluid from thecooling system to the generator, the combination of means responsive toa condition in the system which accompanies excess heating in saidradiator for discharging steam from the inlet end of said generator tosaid cooling system independently of said radiator and without reversingthe flow of fluid from said cooling system to said generator.

4. In an automobile body steam heating system including a steamgenerator and a heater radiator connected in circuit with differentportions of the automobile engine cooling system and having a meteringdevice and a check valve in the connection for conducting fluid from thecooling system to the generator, the combination of a duct connectingthe inlet end of the generator at a point closely adjacent thereto withthe cooling system independently of the heater radiator and a pressurerelease valve in said conduit operable in response to a condition in thesystem which accompanies excess heating in said heater radiator fordischarging steam from the inlet end of said steam generator to saidcooling system through said duct without necessitating its passagethrough said heater radiator.

5. In an automobile body steam heating system including a steamgenerator and a body radiator connected in circuit with differentportions of the automobile engine cooling system and having a meteringdevice and a check valve in the connection for conducting the fluid fromthe cooling system to the generator, the combination of means responsiveto an increase in pressure in said generator which accompanies excessheating in said heater radiator for discharging a portion of the steamgenerated by said generator to said engine cooling system without thenecessity of passing through said heater radiator, comprising a conduitinterposed between the inlet end of said generator and connected theretoat a point closely adjacent to it and said check valve and leading tosaid engine cooling system independently of said radiator.

6. In an automobile body steam heating system including a steamgenerator and a body radiator connected in circuit with differentportions of the automobile engine cooling system and having a meteringdevice in the connection for conducting fluid from the cooling system tosaid generator, of means responsive to an increase in pressure in saidgenerator which accompanies ex cess heating in said radiator for feedinga portion of the steam formed in said generator to said engine coolingsystem independently of said radiator, including, in combination, acheck valve interposed between the inlet end of said steam generator andthe feed pipe conducting fluid from said generator to said coolingsystem.

7. In an automobile body steam heating system including a steamgenerator positioned in the path of flow of exhaust gases from theinternal combustion engine of the automobile, a heater radiator, a ductfor feeding fluid from the engine cooling system to the inlet end of thesteam generator, a duct connecting the outlet end of the steam generatorwith the inlet end of the heater radiator and a duct connecting thedischargeside of the heater radiator with the engine cooling system, thecombination of a check valve for preventing reversal of flow of fluidfrom the steam generator to the engine cooling system through the firstmentioned duct and positioned in said first mentioned duct in closeproximity to point at which the inlet end of the steam generator isfirst subjected to the efiects of the exhaust gases of the engine, aduct communicating at one end with the steam generator on the downstream side of said check valve and connected at its 0pposite end withsaid engine cooling system, and a spring pressed check valve in saidduct permitting fiow of fluid therethrough only in the direction fromsaid generator toward said cooling system.

1 8. The method of operating an automobile body steam heating systemincluding a steam generator adapted to be subjected to the flow ofexhaust gases from an internal combustion engine and a heater radiatorconnected in circuit between different portions of the cooling systemfor said engine, comprising preventing the reversal of flow of fluid inthe heater system at a point in close proximity to the inlet end of thesteam generator and discharging steam from the steam generator directlyto the engine cooling system independently of the heater radiator underthose conditions of engine operation conducive to the formation ofsuper-heated steam in said steam generator.

9. In an automobile body steam heating system including a steamgenerator exposed to theflow of exhaust gases from the internalcombustion engine of the automobile and a heater radiator connected incircuit with different portions of the engine cooling system, the methodof eliminating the deleterious effects of super-heated steam formed inthe steam generator upon the heater radiator comprising preventing thereversal of flow of fluid through the heater system at a point in closeproximity to the point at which the inlet end of the steam generator isfirst subjected to the efiects of said exhaust gases, and automaticallyby-passing steam from the steam generator to the engine cooling systemaround the heater radiator during substantially only those periods ofengine operation conducive to the formation of super-heated steam insaid steam generator.

ROGER W. ANGS'I'MAN.

